Coating materials, method for the production thereof, and use thereof

ABSTRACT

Coating materials including at least one hydroxyl-containing (meth)acrylate (co)polymer, at least one carbamate- and hydroxyl-containing compound and at least one amino resin, where at least 10 equivalent % of the hydroxyl groups present in the (meth)acrylate (co)polymers and/or the carbamate and hydroxyl containing compound are primary hydroxyl groups. The coating materials after curing have a storage modulus E′ in the rubber-elastic range of at least 1.5*10 7  Pa, the storage modulus E′ having been measured by dynamic mechanical thermoanalysis (DMTA) on homogeneous free films with a thickness of 40±10 μm. Also included is a processes for preparing the coating materials and applications therefor.

FIELD OF THE INVENTION

The present invention relates to novel coating materials. The presentinvention also relates to a novel process for preparing coatingmaterials. The present invention further relates to the use of the novelcoating materials for producing coatings, adhesive films and seals,preferably scratchproof coatings, more preferably scratchproofclearcoats, especially for scratchproof multicoat paint systems.

PRIOR ART

In years gone by great advances have been made in the development ofacid-resistant and etch-resistant clearcoats for automotive OEMfinishing. In recent times an increased desire has now arisen on thepart of the automobile industry for scratchproof clearcoats which at thesame time retain the existing level in terms of their other properties.

International patent application WO 98/40442 discloses coating materialswhich lead to scratchproof coatings. These coating materials in thecured state have a storage modulus E′ of at least 10⁷ Pa. The coatingmaterials comprise as binders hydroxyl-functional (meth)acrylatecopolymers having a hydroxyl number of 100 to 240 mg KOH/g, an acidnumber from 0 to 35 mg KOH/g, a number-average molecular weight from1,500 to 10,000 daltons, and a glass transition temperature of not morethan 70° C., more preferably from −40 to +30° C. The hydroxyl-functional(meth)acrylate copolymers ought to contain as many primary hydroxylgroups as possible.

More preferably at least 50 to 100% of the hydroxyl groups present areprimary hydroxyl groups. Crosslinking agents used aretris(alkoxycarbonylamino)-triazine and/or polyisocyanates. The use ofcompounds containing at least one carbamate group and at least onehydroxyl group is not described. The coatings produced from the knowncoating materials possess high scratch resistance, high gloss, goodchemical resistance, and good weathering stability. The etch resistance,on the other hand, leaves something to be desired. Furthermore, it isnecessary to improve the chemical resistance still further in order tosatisfy the heightened requirements of the market.

European patent application EP 0 675 141 A1 discloses a coating materialwhose binder is a methacrylate copolymer with a number-average molecularweight of 3,071 daltons, containing primary hydroxyl groups andcarbamate groups, and whose crosslinking agent is an amino resin. Thebinder is comparatively viscous, and for that reason the coatingmaterial is comparatively difficult to apply. Although the coatingproduced from it has a high gloss, its etch resistance, hardness andimpact strength leave much to be desired.

In order to improve the level of properties of this known coatingmaterial and of the coating produced from it, EP 0 675 141 A1 proposesusing as binder (meth)acrylate copolymers which contain carbamate groupsand sterically hindered secondary hydroxyl groups. It is true that thesebinders may also contain primary hydroxyl groups. As is apparent fromthe examples of the European patent application, however, binderscontaining no primary hydroxyl groups are preferred. These binders havea comparatively low viscosity, and so the coating materials in questionare easier to apply. The coatings produced from them possess goodchemical resistance, etch resistance, hardness, and impact strength, andalso a high gloss. Indications as to the scratch resistance, however,are lacking.

European patent application EP 0 915 113 A1 discloses coating materialscomprising as binders (i) compounds such as (meth)acrylate copolymerscontaining hydroxyl groups and carbamate groups or (ii) compounds suchas (meth)acrylate copolymers containing hydroxyl groups and (iii) acompound containing carbamate groups, and, as crosslinking agents,polyisocyanates and amino resins.

The (meth)acrylate copolymers (ii) have a number-average molecularweight of from 1,000 to 40,000 and a glass transition temperature offrom −20 to +80° C. and contain preferably primary hydroxyl groups (cf.EP 0 915 113 A1, page 5, lines 9 and 10 and page 6, lines 10 to 13).

The compounds (iii) containing carbamate groups may also containhydroxyl groups, the ratio of hydroxyl to carbamate groups beingunspecified. They can thus also be used as binders (i). Whether and, ifso, to what extent the hydroxyl-containing compounds (iii) might also beused in combination with the (meth)acrylate copolymers (ii) is notapparent from EP 0 915 113 A1.

According to the examples of EP 0 915 113 A1 it is preferred to use(meth)acrylate copolymers containing secondary hydroxyl groups andcarbamate groups as binders on their own. Thus, for example, themethacrylate copolymer of example 1 has a carbamate equivalent weightCEW of 493 g/equivalent and a hydroxyl equivalent weight of 493g/equivalent. Data on number-average molecular weight and glasstransition temperature are absent. The multicoat paint systems producedwith the aid of the coating material have a good etch resistance buttheir scratch resistance leaves much to be desired.

European patent EP 0 994 930 B1 discloses coating materials comprising(meth)acrylate copolymer binders containing primary and secondaryhydroxyl groups. The (meth)acrylate copolymers have a number-averagemolecular weight of from 5,000 to 25,000, a hydroxyl equivalent weightof from 300 to 800 g/equivalent and a glass transition temperature of atleast +10° C. The (meth)acrylate copolymers may also contain anunspecified number of carbamate groups. The combination of thecarbamate-free (meth)acrylate copolymers with compounds containingcarbamate groups is as little apparent from the patent as the ratio ofhydroxyl to carbamate groups. Amino resin crosslinking agents are used.

The coatings produced from the known coating materials are intended onthe one hand to have the durability, hardness, gloss and overall opticalappearance normally possessed by the coatings produced from coatingmaterials based on hydroxyl-containing (meth)acrylate copolymers andamino resins and on the other hand to have the etch resistance normallypossessed by the coatings produced from coating materials based onhydroxyl/isocyanate, epoxy/acid, and carbamate/amino resin crosslinkingsystems. The scratch resistance and the chemical resistance,particularly the motor fuel resistance, of these known coatings,however, continues to leave much to be desired.

According to European patent EP 1 042 402 B1 the scratch resistance andabrasion resistance of the coatings produced from the coating materialsknown from European patent EP 0 994 930 B1 are improved by addingtris(alkoxycarbonylamino)triazines (TACT) to the coating materials asadditional crosslinking agents. However, the known coatings do notattain the scratch resistance which must be attained in order thatdamage no longer occurs to the coatings in practice in car washinstallations.

PROBLEMS ADDRESSED BY THE INVENTION

It is an object of the present invention to provide coating materialswhich no longer have the disadvantages of the prior art but whichinstead are stable on storage and easy and convenient to apply.Following application and curing, the novel coating materials shouldproduce coatings which combine a particularly high scratch resistancewith very good chemical resistance and etch resistance, particularly inthe pancreatin, tree resin, and gasoline tests, and very goodappearance. Not least, the novel coating materials should be suitablefor producing coatings, adhesive films, and seals, preferablyscratchproof coatings, more preferably scratchproof clearcoats,especially scratchproof multicoat paint systems for the automotivesector.

SOLUTIONS PROVIDED BY THE INVENTION

The invention accordingly provides the novel coating materials,comprising

-   -   (A) at least one hydroxyl-containing (meth)acrylate (co)polymer        having an OH number of from 100 to 250 mg KOH/g, an acid number        of from 0 to 35 mg KOH/g, a number-average molecular weight        M_(n) of from 1,200 to 20,000 daltons, and a glass transition        temperature of not more than +70° C.,    -   (B) at least one carbamate- and hydroxyl-functional compound        having an OH number of from 10 to 150 mg KOH/g, a carbamate        equivalent weight CEW of from 250 to 700 g/equivalent and an        equivalents ratio of hydroxyl to carbamate groups of from 1:20        to 1:0.5, and    -   (C) at least one amino resin;    -   where    -   (I) at least 10 equivalent% of the hydroxyl groups present in        the (meth)acrylate (co)polymers (A) and/or the compounds (B) are        primary hydroxyl groups and    -   (II) the coating materials after curing have a storage modulus        E′ in the rubber-elastic range of at least 1.5*10⁷ Pa, the        storage modulus E′ having been measured by dynamic mechanical        thermoanalysis (DMTA) on homogeneous free films with a thickness        of 40±10 μm.

The novel coating materials are referred to below as “coating materialsof the invention”.

The invention also provides a novel process for preparing coatingmaterials, in which

-   -   (A) at least one hydroxyl-containing (meth)acrylate (co)polymer,    -   (B) at least one compound containing carbamate groups and        hydroxyl groups,    -   (C) at least one amino resin,    -   are mixed with one another and the resulting mixture is        homogenized, the constituents of the coating materials being        selected such that    -   (I) at least 10 equivalent% of the hydroxyl groups present in        the (meth)acrylate (co)polymers (A) and the compounds (B) are        primary hydroxyl groups and    -   (II) the coating materials after curing have a storage modulus        E′ in the rubber-elastic range of at least 1.5*10⁷ Pa, the        storage modulus E′ having been measured by dynamic mechanical        thermoanalysis on homogeneous free films with a thickness of        40±10 μm.

The novel process for preparing coating materials is referred to belowas “process of the invention”.

Further subject matters of the invention will become apparent from thedescription.

THE ADVANTAGES OF THE INVENTION

In the light of the prior art it was surprising and unforeseeable forthe skilled worker that the object on which the present invention wasbased could be achieved by means of the coating materials of theinvention and by means of the process of the invention.

In particular it was surprising that the coating materials of theinvention produced coatings, particularly clearcoats for multicoat paintsystems on motor vehicle bodies, which were distinguished simultaneouslyby high scratch resistance and by a high level of resistance topancreatin, tree resin, and gasoline, especially FAM standard test motorfuel (50% by volume toluene, 30% by volume isooctane, 15% by volumediisobutylene, 5% by volume ethanol). The test known as the FAM test iscarried out in accordance with VDA [German Automakers' Association] testbulletin 621-412 (based on DIN standard 53 168).

It was also surprising that the coating materials of the invention weresuitable as adhesives and sealants for producing adhesive films andseals and also as starting products for producing self-supporting filmsand moldings.

The adhesive films, seals, self-supporting films and moldings of theinvention likewise had outstanding performance properties.

DETAILED DESCRIPTION OF THE INVENTION

It is critical to the invention that the coating materials and/or theirconstituents are selected such that the cured coating material has astorage modulus E′ in the rubber-elastic range, i.e., an energycomponent (elastic component) which is recoverable in the deformation ofa viscous elastic material such as a polymer, for example, of at least1.5*10⁷ Pa, preferably of at least 5*10⁷ Pa, more preferably of at least8*10⁷ Pa, very preferably of at least 10*10⁷ Pa, and with particularpreference of at least 14*10⁷ Pa, the storage modulus E′ having beenmeasured by dynamic mechanical thermoanalysis (DMTA) on homogeneous freefilms with a thickness of 40±10 μm.

DMTA is a widely known measurement method for determining the viscouselastic properties of coatings and is described, for example, inMurayama, T., Dynamic Mechanical Analysis of Polymeric Materials,Elsevier, New York, 1978 and Loren W. Hill, Journal of CoatingsTechnology, Vol. 64. No. 808, May 1992, pages 31 to 33. The processconditions are described in detail by Th. Frey, K.-H. Grosse Brinkhausand U. Röckrath in cure Monitoring of Thermoset Coatings, Progress inOrganic Coatings 27 (1996), 59-66 or in German patent application DE 4409 715 Al or in German patent DE 197 09 467 C2.

The storage modulus E′ is measured on homogeneous free films. The freefilms are produced conventionally by applying the coating material inquestion to substrates and curing it, the substrates being those towhich the coating produced does not adhere. Examples that may bementioned of suitable substrates include glass, Teflon, and, inparticular, polypropylene. Polypropylene has the advantage of readyavailability and is therefore normally used as support material.Preference is given to employing the following conditions: tensile mode;amplitude: 0.2%; frequency: 1 Hz; temperature ramp: 1° C./min from roomtemperature to 200° C. The measurements can be conducted, for example,with the instruments MK II, MK III or MK IV from the company RheometricScientific.

The specific selection of the coating materials by way of the value ofthe storage modulus E′ in the rubber-elastic range at 20° C. of thecured coating materials makes it possible in a simple way to providecoating materials having the desired good scratch resistance, since theparameter can be determined by means of simple DMTA measurements.

The energy component consumed (dissipated) in the deformation of theviscous elastic material is described by the size of the loss modulusE″. The loss modulus E″ is likewise dependent on the rate of deformationand the temperature. The loss factor tan δ is defined as the quotientformed from the loss modulus E″ and the storage modulus E′. tan δ canlikewise be determined with the aid of DMTA and represents a measure ofthe relationship between the elastic and plastic properties of the film.The loss factor tan δ may vary; preferably at 20° C. it is not more than0.10, preferably not more than 0.06.

The value of the storage modulus E′ can be controlled by way of theselection of the binders and crosslinking agents.

For example, the storage modulus increases as the hydroxyl number of thebelow-described binders (A) and (B) overall goes up and as the carbamateequivalent weight CEW of component (B) goes down and as the proportionof primary hydroxyl groups in the below-described binders (A) and (B)goes up.

The coating materials of the invention comprise at least onehydroxyl-containing (meth)acrylate (co)polymer (A) having a hydroxylnumber of from 100 to 250, preferably from 160 to 220, and morepreferably from 170 to 200 mg KOH/g, an acid number of from 0 to 35 andpreferably from 0 to 25 mg KOH/g, a glass transition temperature of notmore than +70° C. and preferably from −40° C. to +70° C., and anumber-average molecular weight of from 1,200 to 20,000, preferably from1,500 to 15,000 and more preferably from 1,500 to 10,000 daltons. It isimportant that the hydroxyl content of the (meth)acrylate (co)polymer(A) or (B) is chosen so that at least 10%, preferably at least 15%, andmore preferably at least 20 equivalent % of the hydroxyl groups presentin (A) and/or (B) are primary hydroxyl groups. With particularpreference the primary hydroxyl groups originate predominantly, inparticular substantially completely, from component (A). In principle,all (meth)acrylate (co)polymers (A) having the stated characteristics(hydroxyl number, acid number, glass transition temperature andnumber-average molecular weight) are suitable provided that they lead,after crosslinking, to coatings having the stated viscous elasticparameters.

The glass transition temperature can be calculated approximately by theskilled worker with the aid of the formula$\frac{1}{T_{g}} = {\sum\limits_{1}^{1}\frac{W_{i}}{T_{g,i}}}$

-   -   T_(g)=glass transition temperature of the polymer    -   i=number of different copolymerized monomers    -   W_(i)=weight fraction of the ith monomer    -   T_(g,i)=glass transition temperature of the homopolymer of the        ith monomer.

The coating materials are prepared using, for example, methacrylatecopolymers (Al) obtainable by copolymerizing

-   -   (a1) from 10 to 51% by weight, preferably from 20 to 45% by        weight, of 4-hydroxy-n-butyl acrylate or 4-hydroxy-n-butyl        methacrylate or a mixture of 4-hydroxy-n-butyl acrylate and        4-hydroxy-n-butyl methacrylate,    -   (b1) from 0 to 36% by weight, preferably from 0 to 20% by        weight, of a hydroxyl-containing ester of acrylic acid or a        hydroxyl-containing ester of methacrylic acid, other than (a1),        or of a mixture of such monomers,    -   (c1) from 28 to 58% by weight, preferably from 34 to 50% by        weight, of an aliphatic or cycloaliphatic ester of (meth)acrylic        acid having at least 4 carbon atoms in the alcohol residue,        other than (a1) and (b1), or of a mixture of such monomers,    -   (d1) from 0 to 3% by weight, preferably from 0 to 2% by weight,        of an ethylenically unsaturated carboxylic acid or of a mixture        of ethylenically unsaturated carboxylic acids, and    -   (e1) from 0 to 40% by weight, preferably from 5 to 35% by        weight, of a vinylaromatic and/or of an ethylenically        unsaturated monomer other than (a1), (b1), (c1), and (d1), or of        a mixture of such monomers,        the sum of the weight fractions of components (a1), (b1), (c1),        (d1) and (e1) always being 100% by weight.

The preferred glass transition temperature of this methacrylatecopolymer (A1) is from −40 to +70° C.

The coating materials are also prepared using, for example, methacrylatecopolymers (A2) obtainable by copolymerizing

-   -   (a2) from 10 to 51% by weight, preferably from 20 to 45% by        weight, of a hydroxyl-containing methacrylate, preferably        hydroxypropyl methacrylate or hydroxyethyl methacrylate, or a        mixture of such monomers, preferably a mixture of hydroxypropyl        methacrylate and hydroxyethyl methacrylate,    -   (b2) from 0 to 36% by weight, preferably from 0 to 20% by        weight, of a hydroxyl-containing ester of acrylic acid or a        hydroxyl-containing ester of methacrylic acid, other than (a2),        or of a mixture of such monomers,    -   (c2) from 28 to 58% by weight, preferably from 34 to 50% by        weight, of an aliphatic or cycloaliphatic ester of (meth)acrylic        acid having at least 4 carbon atoms in the alcohol residue,        other than (a2) and (b2), or of a mixture of such monomers,    -   (d2) from 0 to 3% by weight, preferably from 0 to 2% by weight,        of an ethylenically unsaturated carboxylic acid or of a mixture        of ethylenically unsaturated carboxylic acids, and    -   (e2) from 0 to 40%, preferably from 5 to 35% by weight, of a        vinylaromatic and/or of an ethylenically unsaturated monomer        other than (a2), (b2), (c2), and (d2), or of a mixture of such        monomers,        the sum of the weight fractions of components (a2), (b2), (c2),        (d2) and (e2) always being 100% by weight.

The preferred glass transition temperature of this methacrylatecopolymer (A2) is from −40 to +70° C.

The (meth)acrylate (co)polymers (A) used with preference in accordancewith the invention, especially the methacrylate copolymers (A1) and(A2), can be prepared by polymerization methods which are well andgenerally known. Polymerization methods for preparing polyacrylateresins are common knowledge and have been described in many instances(cf. e.g. Houben-Weyl, Methoden der organischen Chemie, 4^(th) Edition,Volume 14/1, pages 24 to 255 (1961)).

The (meth)acrylate (co)polymers (A) used with preference in accordancewith the invention are prepared in particular with the aid of thesolution polymerization method. In this case usually an organic solventor solvent mixture is introduced as an initial charge, which is heatedto boiling. The monomer mixture to be polymerized, together with one ormore polymerization initiators, is then added continuously to thisorganic solvent or solvent mixture. The polymerization takes place attemperatures between 100 and 160° C., preferably between 130 and 150° C.Polymerization initiators used are preferably initiators which form freeradicals. The type and amount of initiator are normally chosen so thatthe supply of free radicals during the feed phase at the polymerizationtemperature is very largely constant.

Examples of initiators which can be used include the following: dialkylperoxides, such as di-tert-butyl peroxide and dicumyl peroxide;hydroperoxides, such as cumene hydroperoxide and tert-butylhydroperoxide; peresters, such as tert-butyl perbenzoate, tert-butylperpivalate, and tert-butyl per-2-ethylhexanoate; and bisazo compoundssuch as azobisisobutyronitrile.

The polymerization conditions (reaction temperature, feed time of themonomer mixture, amount and type of organic solvents and polymerizationinitiators, possible use of molecular weight regulators, such asmercaptans, thioglycolates, and hydrogen chlorides) are selected suchthat the polyacrylate resins used with preference have a number-averagemolecular weight of from 1,200 to 20,000, preferably from 1,500 to15,000, more preferably from 1,500 to 10,000 daltons (determined by gelpermeation chromatography using a polystyrene standard).

The acid number of the (meth)acrylate (co)polymers (A) used inaccordance with the invention can be set by the skilled worker usingappropriate amounts of carboxyl-functional monomers. The same applies tothe setting of the hydroxyl number, which can be controlled by way ofthe amount of hydroxyl-functional monomers used.

As component (a1) it is possible to use 4-hydroxy-n-butyl acrylate,4-hydroxy-n-butyl methacrylate or a mixture of 4-hydroxy-n-butylacrylate and 4-hydroxy-n-butyl methacrylate. In one preferred embodimentthe component (al) used is 4-hydroxy-n-butyl acrylate.

As component (a2) it is possible to use hydroxyalkyl esters ofmethacrylic acid, particularly those in which the hydroxyalkyl groupcontains up to 8, preferably up to 6, and more preferably up to 4 carbonatoms, or mixtures of these hydroxyalkyl esters. Examples of suchhydroxyalkyl esters include 2-hydroxypropyl methacrylate,3-hydroxypropyl methacrylate and 2-hydroxyethyl methacrylate.

As component (b1) and, respectively, (b2) it is possible in principle touse any hydroxyl-containing ester of acrylic acid or methacrylic acidother than (a1) or (a2), or a mixture of such monomers. Examples of (b1)and (b2) include the following: hydroxyalkyl esters of acrylic acid,such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate,3-hydroxypropyl acrylate or 3-hydroxybutyl acrylate and hydroxyalkylesters of methacrylic acid, such as hydroxyethyl methacrylate andhydroxypropyl methacrylate, and also the esterification products ofhydroxyalkyl (meth)acrylates with one or more molecules ofε-caprolactone. Also suitable are reaction products of acrylic and/ormethacrylic acid with a glycidyl ester. Glycidyl esters can be obtainedby reacting a monofunctional carboxylic acid (e.g., octanoic acid,benzoic acid, benzilic acid, cyclohexanoic acid) with an epihalohydrin(e.g., epichlorohydrin) under the known reaction conditions. Glycidylesters are available commercially, for example, as Cardura® E fromShell, Glydexx® N-10 from Exxon or Araldit® PT910 from Ciba. Glycidylesters may be represented by the following formula:

in which R is a substituted or unsubstituted hydrocarbon radical having1 to 40, preferably 1 to 20, and more preferably 1 to 12 carbon atoms.Polyglycidyl esters may likewise be used and are preparable by reactinga polyfunctional carboxylic acid (e.g. phthalic acid, thioglycolic acid,adipic acid) with an epihalohydrin. Polyglycidyl esters may likewise berepresented by the above formula. In this case, R is substituted by oneor more glycidyl ester groups. Preference is given to using thecommercial products sold under the brand name Cardura®, Glydeex® orAraldit®.

As component (c1) and, respectively, (c2) it is possible in principle touse any aliphatic or cycloaliphatic ester of (meth)acrylic acid havingat least 4 carbon atoms in the alcohol residue, other than (a1) or (a2)and (b1) or (b2), or a mixture of such monomers. Examples include thefollowing: aliphatic esters of (meth)acrylic acid with 4 to 20 carbonatoms in the alcohol residue, such as n-butyl, iso-butyl, tert-butyl,2-ethylhexyl, stearyl and lauryl methacrylate, and cycloaliphatic estersof (meth)acrylic acid such as cyclohexyl methacrylate, for example.

As component (d1) or (d2) it is possible in principle to use anyethylenically unsaturated carboxylic acid or a mixture of ethylenicallyunsaturated carboxylic acids. As component (d1) or (d2) it is preferredto use acrylic acid and/or methacrylic acid.

As component (e1) or (e2) it is possible in principle to use anyethylenically unsaturated monomer other than (a1) or (a2), (b1) or (b2),(c1) or (c2) and (d1) or (d2), or a mixture of such monomers. Examplesof monomers which can be used as component (e1) or (e2) include thefollowing: vinylaromatic hydrocarbons, such as styrene, α-alkylstyreneand vinyltoluene, amides of acrylic acid and methacrylic acid, such asmethacrylamide and acrylamide; nitrites of methacrylic acid and acrylicacid; vinyl ethers and vinyl esters. As component (e) it is preferred touse vinylaromatic hydrocarbons, especially styrene.

The coating materials of the invention comprise at least one compound B)which bears carbamate groups and hydroxyl groups.

The compound B) has a hydroxyl number of from 10 to 150, preferably from15 to 120, and more preferably from 20 to 100 and a carbamate equivalentweight CEW of from 250 to 700, preferably from 300 to 600, morepreferably from 350 to 500, and with very particular preferance from 360to 450.

The ratio of hydroxyl groups to carbamate groups in the compound B) isfrom 1:20 to 1:0.5, preferably from 1:15 to 1:0.8, and more preferablyfrom 1:10 to 1:1.

Carbamate groups can be obtained in various ways. It is possible, forexample, to react cyclic carbonate groups, epoxy groups, and unsaturatedbonds to form carbamates.

Cyclic carbonate groups can be converted to carbamate groups by reactingthem with ammonia or primary amines, with the ring of the cycliccarbonate group being opened and a β-hydroxyl carbamate being formed.

Epoxy groups can be converted into carbamate groups by reacting themfirst with CO₂ to form a cyclic carbonate, after which the furtherreaction can then take place as outlined above. The reaction with CO₂can take place at pressures between atmospheric pressure andsupercritical CO₂, it being preferred to carry out the reaction undersuperatmospheric pressure (e.g., from 400 to 1050 kPa). The temperaturefor carrying out this reaction is preferably between 60 and 150° C.Catalysts which can be used when carrying out this reaction are thosewhich activate an oxirane ring, such as tertiary amines or quaternarysalts (e.g., tetramethylammonium bromide), combinations of complexorganotin halides and alkylphosphonium halides (e.g., (CH₃)₃SnI,(C₄H₉)₃SnI, Bu₄PI and (CH₃)₄PI), potassium salts (e.g., K₂CO₃, KI)preferably in combination with crown ethers, tin octoate, calciumoctoate, and the like.

Unsaturated bonds can be converted to carbamates by reacting them firstwith peroxide to give epoxides, then with CO₂ to give cyclic carbonates,and thereafter with ammonia or primary amines to give carbamates.

The carbamate may be primary, i.e., ending in an NH₂ group, orsecondary, i.e., ending in an NHR group where R is an organic radical.In a preferred embodiment the carbamate is primary.

Another way to obtain compounds (B) is to react an alcohol (an alcoholbeing a compound bearing one or more hydroxyl groups) With more than oneurea compound in order to obtain a compound which bears carbamategroups. This reaction is carried out with heating of a mixture ofalcohol and urea. It is preferred to add a catalyst.

Another possibility is the reaction of an alcohol with cyanic acid(HOCN) to produce a compound having primary carbamate groups.

Carbamates may likewise be obtained by reacting an alcohol with phosgenefollowed by a reaction with ammonia, giving compounds having primarycarbamate groups, or they can be obtained by reacting an alcohol withphosgene followed by reaction with a primary amine, in which casecompounds having secondary carbamate groups result.

A further way is to react an isocyanate (e.g., HDI, IPDI) with acompound such as hydroxypropyl carbamate to give a carbamate-blockedisocyanate derivative.

Introducing the carbamate group into the compound B) can also be done,if compound B) is a polymer, by incorporating monomers which containcarbamate groups. Examples of suitable monomers of this kind areethylenically unsaturated monomers which contain a carbamate group.

One possibility is to prepare a (meth)acrylic monomer having a carbamatefunction in the ester moiety of the monomer. Such monomers are known andare described in, for example, American patents U.S. Pat. No. 3,479,328A, U.S. Pat. No. 3,674,838 A, U.S. Pat. No. 4,126,747 A, U.S. Pat. No.4,279,833 A and U.S. Pat. No. 4,340,497 A.

Further methods of obtaining the monomers are known to the skilledworker and may likewise be employed.

The acrylic monomer, together where appropriate with other ethylenicallyunsaturated monomers, can then be (co)polymerized by methods which arecommon knowledge.

Alternatively, the carbamate group may be introduced into the compoundB) by means of polymer-analogous reactions. Examples of suitable methodsof this kind are known from patents U.S. Pat. No. 4,758,632 A, U.S. Pat.No. 4,301,257 A or U.S. Pat. No. 2,979,514 A.

One possibility of preparing carbamate-functional polymers by apolymer-analogous route is to carry out thermal cleavage of urea in thepresence of a hydroxyl-functional (meth)acrylate (co)polymer (in orderto liberate ammonia and HNCO), which then gives a carbamate-functional(meth)acrylate (co)polymer.

It is likewise possible to react the hydroxyl group of a hydroxyalkylcarbamate with the isocyanate group of an isocyanate-functional acrylicor vinylic monomer to give a carbamate-functional component.Isocyanate-functional (meth)acrylates are known and are described in,for example, U.S. Pat. No. 4,301,257 A. Isocyanate-functional vinylmonomers are likewise known and include olefinically unsaturatedm-tetramethylxylene isocyanate (available under the name TMI® fromAmerican Cyanamid).

Yet another possibility is to react cyclic carbonate groups of a polymercontaining such groups with ammonia in order to form a polymer whichcontains carbamate groups. Polymers containing cyclic carbonate groupsare likewise known and are described in, for example, U.S. Pat. No.2,979,514 A.

A somewhat more complicated but likewise possible route to thepreparation of polymers containing carbamate groups is thetransesterification of a (meth)acrylate (co)polymer with a hydroxyalkylcarbamate.

Also conceivable is the preparation of the compounds (B) by the reactionof hydroxyl-containing polymers with phosgene and subsequently withammonia, as described in, for example, DE 199 46 048 and DE 101 29 969.

A preferred route, however, is to react an existing polymer, such as a(meth)acrylate (co)polymer, for example, with another component in orderto attach a carbamate group to the existing polymer backbone, as isdescribed in, for example, U.S. Pat. No. 4,758,632 A.

Carbamates can be obtained with preference by polymer-analogoustranscarbamation. In this case an alcohol is caused to react with analkyl carbamate (e.g., methyl carbamate, ethyl carbamate, butylcarbamate) to give a compound containing primary carbamate groups. Thisreaction is carried out with heating, preferably in the presence of acatalyst, such as organometallic catalysts (e.g., dibutyltin dilaurate).

Further possibilities for the preparation of carbamates are known to theskilled worker and are described in, for example, P. Adams F. Baron,“Esters of Carbamic Acid”, Chemical Review, v. 65, 1965.

In the preparation of these compounds (B) it should be ensured, in thecase of subsequent introduction of the carbamate group, for example,that both hydroxyl groups and carbamate groups are present in sufficientnumber in the final compound (B).

Compound (B) is preferably polymeric.

Suitable polymers (B) come from the polymer classes of the random,alternating and/or block, linear and/or branched and/or comb, addition(co)polymers of ethylenically unsaturated monomers, or polyadditionresins and/or polycondensation resins. For further details of theseterms refer to Römpp Lexikon Lacke und Druckfarben, Georg Thieme Verlag,Stuttgart, New York, 1998, page 457, “Polyaddition” and “Polyadditionresins (Polyadducts)”, and also pages 463 and 464, “Polycondensates”,“Polycondensation”, and “Polycon-densation resins”.

Examples of highly suitable addition (co)polymers (B) are (meth)acrylate(co)polymers and partially hydrolyzed polyvinyl esters, especially(meth)acrylate (co)polymers.

Examples of highly suitable polyaddition resins and/or polycondensationresins (B) are polyesters, alkyds, polyurethanes, polylactones,polycarbonates, polyethers, epoxy resin-amine adducts, polysiloxanes,polyureas, polyamides or polyimides, especially polyesters.

With very particular preference the polymers (B) come from the polymerclasses of (meth)acrylate (co)polymers.

Processes for preparing the carbamate-functional polymers (B) which comefrom the aforementioned polymer classes are known from patentapplications

-   -   EP 0 675 141 B1, page 2 line 44 to page 5 line 15 and page 8        line 5 to page 10 line 41, and    -   EP 0 915 113 A1, Example 1, page 11 lines 3 to 15.

The polymers (B) are preferably prepared by copolymerizing a monomermixture comprising at least one olefinically unsaturated carboxylicacid, methacrylic acid for example, in the presence of a glycidyl esterof Versatic® acid (cf. Römpp Lexikon Lacke und Druckfarben, Georg ThiemeVerlag, Stuttgart New York, 1998 “Versatic® Acids”, pages 605 and 606)and then reacting the resultant hydroxyl-containing (meth)acrylate(co)polymer with at least one alkyl carbamate, such as methyl, propyl,or butyl carbamate.

As compound (B) consideration may also be given to a (meth)acrylatecopolymer (B1) obtainable by copolymerizing

-   -   (a) from 10 to 50%, preferably from 10 to 40% by weight, more        preferably from 20 to 30% by weight of a hydroxyl-containing        (meth)acrylate or of a mixture of such monomers,    -   (b) from 0 to 50% by weight, preferably from 10 to 40% by        weight, of a monomer containing at least one carbamate group,        the carbamate group being a reaction product of an epoxide and        an acid with subsequent reaction of the resultant hydroxyl group        to form carbamate, or of a mixture of such monomers,    -   (c) from 5 to 58% by weight, preferably from 5 to 45% by weight,        of an aliphatic or cycloaliphatic ester of (meth)acrylic acid        having at least 4 carbon atoms, preferably at least 6 carbon        atoms, in the alcohol residue, other than (a) and (b), or of a        mixture of such monomers,    -   (d) from 0 to 3% by weight, preferably from 0 to 2% by weight,        of an ethylenically unsaturated carboxylic acid or of a mixture        of ethylenically unsaturated carboxylic acids and    -   (e) from 0 to 40% by weight, preferably from 5 to 35% by weight,        of an ethylenically unsaturated monomer other than (a), (b),        (c), and (d), or of a mixture of such monomers,        the sum of the weight fractions of components (a), (b), (c), (d)        and (e) always being 100% by weight.

The equivalents ratio of hydroxyl groups to monomer containing carbamategroups in this (meth)acrylate copolymer (Bl) is preferably from 1:0.5 to1:0.9.

Components (a), (c), (d) and (e) here correspond to the componentsalready described above for the (meth)acrylate (co)polymers (A).

Component (b) is a monomer containing at least one carbamate group, thecarbamate group being a product of the reaction of an epoxide and anacrylically unsaturated acid with subsequent reaction of the resultanthydroxyl group to carbamate, or a mixture of such monomers.

Alternatively it is preferred to prepare a (meth)acrylate (co)polymer(B) from components (a) to (e), where component

-   -   (b) is from 0 to 50% by weight, preferably from 10 to 40% by        weight, of a monomer which itself is a reaction product of an        epoxide and an acid        and then, in the resulting (meth)acrylate (co)polymer, to react        the hydroxyl group resulting from the reaction of an epoxide and        an acid of component (b) with an alkyl carbamate.

It is preferred if the alkyl carbamate used is methyl carbamate.

In one preferred embodiment the epoxide is a monoepoxide, preferably anepoxy ester, such as one of the glycidyl esters described above in thedescription of the components (b1) and/or (b2).

The epoxides described are reacted with an unsaturated, acid-functionalcompound in order to open the oxirane ring. Here it is possible, forexample, to use acrylic acid and/or methacrylic acid.

The compounds (b) contain an α,β-ethylenically unsaturated organicradical by way of which they can be polymerized into the (meth)acrylate(co)polymer. The epoxide can be reacted before, during or after thepolymerization. Where this reaction takes place during or after thepolymerization, appropriate measures, which are common knowledge, mustbe taken to ensure that even after the reaction the resultant(meth)acrylate (co)polymer (B) contains hydroxyl groups and carbamategroups in sufficient number.

The ratio of all hydroxyl groups from constituents (A) and (B) to thecarbamate groups from component (B) is preferably from 1:10 to 1:0.5,more preferably from 1:5 to 1:0.5, and with very particular preferencefrom 1:2 to 1:1.

The oligomers and polymers (B) preferably have a number-averagemolecular weight of from 600 to 20,000, preferably from 800 to 15,000,more preferably from 1,000 to 10,000, with very particular preferencefrom 1,200 to 8,000, and in particular from 1,200 to 6,000 daltons.

The coating materials used in the process for producing scratchproofcoatings comprise amino resins (C) as crosslinking agents.

These resins (C) are condensation products of aldehydes, especiallyformaldehyde, with, for example, urea, melamine, guanamine andbenzoguanamine. The amino resins contain alcohol groups, preferablymethylol groups, which in general are partly or, preferably, fullyetherified with alcohols. Use is made in particular ofmelamine-formaldehyde resins etherified with lower alcohols,particularly with methanol or butanol. Very particular preference isgiven to using as crosslinking agents melamine-formaldehyde resins whichare etherified with lower alcohols, especially with methanol and/orethanol and/or butanol, and which on average still contain from 0.1 to0.25 nitrogen-bonded hydrogen atoms per triazine ring.

In this context it is possible to use any amino resins suitable fortransparent topcoat or clearcoat materials, or a mixture of such resins.Particularly suitable are the conventional amino resins, some of whosemethylol and/or methoxymethyl groups have been defunctionalized by meansof carbamate or allophanate groups. Crosslinking agents of this kind aredescribed in patents U.S. Pat. No. 4,710,542 A and EP 0 245 700 B1 andalso in the article by B. Singh and Coworkers, “CarbamylmethylatedMelamines, Novel Crosslinkers for the Coatings Industry” in AdvancedOrganic Coatings Science and Technology Series, 1991, Volume 13, pages193 to 207. On the melamine resins reference may also be made to RömppLexikon Lacke und Druckfarben, 1988, pages 374 and 375, “Melamineresins” and to the book “Lackadditive” [Additives for Coatings] by JohanBieleman, 1988, pages 242 to 250, section on“Melamine-resin-crosslinking systems”.

It is particularly preferred here if the crosslinking agent (C) is richin melamine resin; that is accordingly is a melamine resin or aminoresin mixture with a melamine resin fraction of at least 60% by weight,preferably at least 70% by weight, in particular at least 80% by weight,based in each case on the amino resin mixture.

Melamine resins are well known to the skilled worker and are supplied bynumerous companies as sales products:

Examples of suitable, low molecular mass, fully etherified melamineresins are Cymel® 301 and 303 from Cytec, Luwipal® 066 from BASFAktiengesellschaft, Resimene® and Maprenal® MF from Solutia.

Examples of suitable, comparatively low molecular mass, highlyetherified melamine resins containing free imino groups are Cymel® 325and 327 (methanol-etherified) and 1158 (butanol-etherified) from Cytec,Luwipal® 062 (methanol-etherified), 018 (butanol-etherified), and 014(butanol-etherified, of relatively high viscosity) from BASFAktiengesellschaft, Maprenal® MF 927 and 3950 (methanol-etherified), VMF3611 and 3615 (butanol-etherif ied) and 580 (isobutanol-etherified), andalso Resimene® 717 and 718 (methanol-etherified), and 750 and 5901(butanol-etherified) from Solutia, and Setamine® US 138 and US 146(butanol-etherified) from Akzo Resins.

Examples of suitable, comparatively low molecular mass, partiallyetherified melamine resins are Luwipal® 012, 016, 015 and 010 from BASFAktiengesellschaft, Maprenal® MF 590 and 600 from Solutia and Setamine®US 132 and 134 from Akzo Resins.

The coating materials of the invention may where appropriate comprise atleast one further crosslinking agent (D), which is different than theamino resins (C). They are selected from the group consisting ofconventional crosslinking agents which crosslink with the hydroxylgroups of (A) and/or (B) to form ethers and/or esters, such asanhydrides, for example, and/or the conventional blocked and/ornonblocked polyisocyanates, such as are described, for example, inGerman patent application DE 199 14 896 A1. Where blockedpolyisocyanates (D) are present the coating materials of the inventionare one-component systems. Where free polyisocyanates (D) are used thecoating materials of the invention are two-component systems.

As additional crosslinker (D) it is possible in principle to use anypolyisocyanate which can be employed in the coatings field, where amixture of such polyisocyanates, provided the cured coatings exhibit theabovementioned viscoelastic properties. It is preferred, however, to usepolyisocyanates whose isocyanate groups are attached to aliphatic orcycloaliphatic radicals. Examples of such polyisocyanates arehexamethylene diisocyanate, isophorone diisocyanate,trimethylhexamethylene diisocyanate, dicyclohexylmethane diisocyanate,and 1,3-bis(2-isocyanatoprop-2-yl)benzene (TMXDI), 1,3- and1,4-bis(isocyanatomethyl)cyclohexane, and adducts of thesepolyisocyanates with polyols, especially low molecular mass polyols,such as trimethylolpropane, for example, and polyisocyanates that arederived from these polyisocyanates and contain isocyanurate groupsand/or biuret groups. As polyisocyanates it is particularly preferred touse hexamethylene diisocyanate and isophorone diisocyanate,polyisocyanates derived from these diisocyanates and containingisocyanurate and/or biuret groups, and preferably containing more than 2isocyanate groups in the molecule, and also reaction products ofhexamethylene diisocyanate and isophorone diisocyanate or of a mixtureof hexamethylene diisocyanate and isophorone diisocyanate with 0.3 to0.5 equivalent of a low molecular mass polyol having a molecular weightof from 62 to 500, preferably from 104 to 204, in particular of a triol,such as trimethylolpropane, for example.

For the blocking of the polyisocyanates it is possible in principle touse any blocking agent which can be used to block polyisocyanates andhas a sufficiently low deblocking temperature. Blocking agents of thiskind are well known to the skilled worker and need no furtherelucidation here. It is preferred to use blocked polyisocyanates whichcontain isocyanate groups blocked both with a blocking agent (1) andwith a blocking agent (II), the blocking agent (1) being a dialkylmalonate or a mixture of dialkyl malonates, the blocking agent (II)being a CH-acidic blocking agent other than (1), or an oxime or amixture of these blocking agents, and the equivalents ratio between theisocyanate groups blocked with (1) and the isocyanage groups blockedwith (II) being between 1.0:1.0 and 9.0:1.0, preferably between 8.0:2.0and 6.0:4.0, with particular preference between 7.5:2.5 and 6.5:3.5.

Blocking agents (1) used are dialkyl malonates or a mixture of dialkylmalonates. As examples of dialkyl malonates that can be used mention maybe made of dialkyl malonates having 1 to 6 carbon atoms in each of thealkyl radicals, such as, for example, dimethyl malonate and diethylmalonate, preference being given to the use of diethyl malonate.

Blocking agents (II) used are blocking agents containing activemethylene groups, other than (1), and also oximes and mixtures of theseblocking agents. Examples of blocking agents (II) include the following:methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decylor dodecyl acetoacetate, acetone oxime, methyl ethyl ketoxime,acetylacetone, formaldoxime, acetaldoxime, benzophenoxime, acetoxime anddiisobutyl ketoxime. As blocking agent (II) it is preferred to use analkyl acetoacetate having 1 to 6 carbon atoms in the alkyl radical or amixture of such alkyl acetoacetates or a ketoxime or a mixture ofketoximes. Particular preference is given to using alkyl acetoacetatesor methyl ethyl ketoxime as blocking agent(s) (II).

Compounds suitable as further blocking agents include dimethylpyrazoleand/or triazoles.

The amount of the above-described essential constituents (A) and (B) inthe coating materials of the invention may vary widely and is guided bythe requirements of the case in hand, in particular by the functionalityof complementary reactive groups in components (A) and (B) on the onehand and the crosslinking agents (C) and, if appropriate, (D) on theother. The amount of the binders (A)+(B) is preferably from 30 to 80%,more preferably from 35 to 75%, with particular preference from 40 to70%, with very particular preference from 45 to 65% and in particularfrom 50 to 60% by weight, based in each case on the solid of thecomposition of the invention; the amount of the crosslinking agents(C)+(D) is preferably from 20 to 70%, more preferably from 25 to 65%,with particular preference from 30 to 60%, with very particularpreference from 35 to 55%, and in particular from 40 to 50% by weight,based in each case on the solids of the composition of the invention,and the weight ratio of components (C) to (D) is 0:1 to 1:10, preferably0.2:1 to 1:0.2, with particular preference 0.5:1 to 1:0.5.

Furthermore, the coating materials of the invention may also comprise atleast one conventional additive (E) selected from the group consistingof binders other than the above-described binders (A) and (B),especially hydroxyl-containing binders; reactive diluents; molecularlydispersipbly soluble dyes; light stabilizers, such as UV absorbers andreversible free-radical scavengers (HALS); antioxidants; low-boiling andhigh-boiling (“long”) organic solvents; devolatilizers; wetting agents;emulsifiers; slip additives; polymerization inhibitors; crosslinkingcatalysts; adhesion promoters; leveling agents; film-formingauxiliaries; Theological aids, such as thickeners and pseudo-plastic sagcontrol agents, SCAs; flame retardants; corrosion inhibitors; free-flowaids; waxes; siccatives; biocides; and flatting agents.

Examples of suitable additives (E) are described in detail in thetextbook “Lackadditive” by Johan Bieleman, Wiley-VCH, Weinheim, NewYork, 1998, in D. Stoye and W. Freitag (Editors), “Paints, Coatings andSolvents”, second, completely revised edition, Wiley-VCH, Weinheim, NewYork, 1998, “14.9. Solvent Groups”, pages 327 to 373.

The coating materials of the invention comprising the constituentsdescribed above are used in particular as clearcoat materials forproducing clearcoats or as starting products for the production ofclear, transparent self-supporting films and moldings.

Alternatively, the coating materials of the invention may be pigmented.In that case they preferably comprise at least one conventional pigment(F) selected from the group consisting of organic and inorganic,transparent and opaque, color and/or effect, electrically conductive,magnetically shielding and fluorescent pigments, fillers, andnanoparticles.

The pigmented coating materials of the invention are used in particularas electrocoat materials, surfacers, basecoat materials and solid-colortopcoat materials for producing electrocoats, surfacer coats orantistonechip primer coats, basecoats and solid-color topcoats, or forproducing pigmented self-supporting films and moldings.

Where exclusively nonopaque pigments (F) are used, especiallynanoparticles, the pigmented coating materials of the invention may alsobe used as clearcoat materials or for producing clear, transparentself-supporting films and moldings.

In terms of method, the preparation of the coating materials of theinvention has no particular features but instead takes place by mixingand homogenizing the above-described constituents using conventionalmixing techniques and apparatus such as stirred tanks, stirrer mills,extruders, compounders, Ultraturrax, inline dissolvers, static mixers,micromixers, toothed-wheel dispersers, pressure release nozzles and/ormicrofluidizers, if appropriate with the exclusion of actinic radiation.It is essential here, however, to select the constituents of the coatingmaterials of the invention such that, after they have been cured, thecoating materials of the invention have the above-described,DMTA-determined mechanical-dynamic properties.

The resultant coating materials of the invention are, in particular,conventional coating materials comprising organic solvents. However,they may also be aqueous compositions, substantially or completelysolvent-free and water-free liquid compositions (100% systems),substantially or completely solvent-free and water-free solid powders orsubstantially or completely solvent-free powder suspensions (powderslurries).

The coating materials of the invention are applied to conventionaltemporary or permanent substrates. For producing self-supporting filmsand moldings of the invention it is preferred to use conventionaltemporary substrates, such as metal belts and polymer belts or hollowbodies made of metal, glass, plastic, wood or ceramic, which can easilybe removed without damaging the self-supporting films and moldings ofthe invention.

Where the coating materials of the invention are used for producingcoatings, adhesive films and seals, permanent substrates are used, suchas motor vehicle bodies and parts thereof, the interior and exterior ofbuildings and parts thereof, doors, windows, furniture, hollowglassware, coils, freight containers, packaging, small parts, electricalcomponents, and components for white goods. The self-supporting filmsand moldings of the invention may likewise serve as substrates. Furtherexamples of suitable substrates are known from German patentapplications DE 199 24 172 A1, page 8 lines 21 to 37 or DE 199 30 067A1, page 13 line 61 to page 14 line 16.

In terms of method, the application of the coating materials of theinvention has no special features but can instead take place by anyconventional application method suitable for the composition inquestion, such as, for example, electrocoating, spraying, squirting,knifecoating, brushing, flowcoating, dipping, trickling or rolling. Itis preferred to employ spray application methods, unless thecompositions in question are powders.

The application of the powders does not have particular features interms of method either but instead takes place, for example, inaccordance with the conventional fluid-bed methods, such as are known,for example, from the BASF Coatings AG brochures “Pulverlacke fürindustrielle Anwendungen”, January 2000, or “Coatings Partner,Pulverlack Spezial”, 1/2000, or from Römpp Lexikon Lacke undDruckfarben, Georg Thieme Verlag, Stuttgart, New York, 1998, pages 187and 188, “Electrostatic Powder Spraying”, “Electrostatic Spraying” and“Electrostatic Fluid-Bath Process”.

The coating materials of the invention are used preferably for producingmoldings and self-supporting films or as coating materials, adhesives,and sealants for producing coatings, adhesive films and seals. Inparticular, the coating materials are used for producing multicoat colorand/or effect paint systems by the conventional wet-on-wet methods (cf.,for example, German patent applications DE 199 14 896 A1, column 16 line54 to column 18 line. 57, and DE 199 30 067 A1, page 15 line 25 to page16 line 36).

The curing of the applied coating materials of the invention likewisehas no special features in terms of method but instead takes place withthe aid of the conventional methods, such as thermally in particular,for example by heating in a forced-air oven or irradiation with IRlamps.

The coating compositions of the invention are used preferably forproducing multicoat paint systems or in processes for producingmulticoat paint systems, in that case preferably as topcoat material,particularly in the area of automotive OEM finishing. The presentinvention accordingly further provides a process for producing multicoatpaint systems, in which

-   -   (1) a pigmented basecoat material is applied to the substrate        surface,    -   (2) from the basecoat material a polymer film is formed,    -   (3) a transparent topcoat material is applied to the resulting        basecoat film, and then    -   (4) the basecoat film and topcoat film are cured together,        which comprises using a coating composition of the invention in        at least one of the coating films. In this process it is        preferred to use a coating composition of the invention as        topcoat material.

In stage (1) of the process of the invention it is possible in principleto use all pigmented basecoat materials which are suitable for producingtwo-coat paint systems. Basecoat materials of this kind are well knownto the skilled worker. Not only water-thinnable basecoat materials butalso those based on organic solvents can be used. Suitable basecoatmaterials are described, for example, in U.S. Pat. No. 3,639,147 A1, DE33 33 072 A1, DE 38 14 853 A1, GB 2 012 191 A, U.S. Pat. No. 3,953,644A1, EP 0 260 447 A1, DE 39 03 804 A1, EP 0 320 552 A1, DE 36 28 124 A1,U.S. Pat. No. 4,719,132 A1, EP 0 297 576 A1, EP 0 069 936 A1, EP 0 089497 A1, EP 0 195 931 A1, EP 0 228 003 A1, EP 0 038 127 A1 and DE 28 18100 A1. These patent documents are also a source of further informationon the basecoat/clearcoat process in question.

The resultant coatings and self-supporting films of the invention,particularly the single-coat or multicoat color and/or effect paintsystems and clearcoats of the invention, especially the clearcoats, areeasy to produce and have outstanding optical properties (appearance) andvery high light stability, chemical resistance, water resistance,condensation resistance, weathering stability, and etch resistance. Inparticular they are free from turbidity and inhomogeneity. They have anoutstanding scratch resistance and abrasion resistance in combinationwith an outstanding surface hardness and acid resistance. Surprisinglythe coatings, especially the clearcoats, when exposed to the realisticAMTEC test, only suffer a difference in gloss before and after exposureof less than 35, preferably less than 30, and in particular less than 25units, which underlines their particularly high scratch resistance.

The adhesive films of the invention join a wide variety of substratesfirmly and durably to one another and have a high chemical andmechanical stability even under conditions of extreme temperature and/ortemperature fluctuation.

Similarly, the seals of the invention seal the substrates permanentlyand exhibit a high chemical and mechanical stability even underconditions of extreme temperature and/or temperature fluctuation andeven in conjunction with exposure to aggressive chemicals.

Accordingly, the primed or unprimed substrates that are commonlyemployed in the technology fields addressed above and which have beencoated with at least one coating of the invention, bonded with at leastone adhesive film of the invention, sealed with at least one seal of theinvention and/or wrapped or packaged with at least one self-supportingfilm of the invention or at least one molding of the invention combine aparticularly advantageous profile of performance properties with aparticularly long service life, which makes them particularly attractiveboth economically and environmentally.

EXAMPLES Preparation Example 1

The preparation of a methacrylate copolymer (A)

A laboratory reactor with a useful volume of 4 l, equipped with astirrer, two dropping funnels for the monomer mixture and initiatorsolution respectively, a nitrogen inlet pipe, thermometer, and refluxcondenser, was charged with 601 g of an aromatic hydrocarbons fractionhaving a boiling range from 158° C. to 172° C. The solvent was heated to140° C. When 140° C. had been reached, a monomer mixture of 225.4 g ofstyrene, 169 g of n-butyl methacrylate, 293 g of cyclohexyl acrylate,225.4 g of hydroxypropyl methacrylate, 202.8 g of 2-hydroxyethylmethacrylate and 11.2 g of acrylic acid was metered into the reactor ata uniform rate over the course of 4 hours and an initiator solution of112.6 g of t-butyl perethylhexanoate in 40 g of the aromatic solventdescribed was metered into the reactor at a uniform rate over the courseof 4.5 hours. The metering of the monomer mixture and of the initiatorsolution was commenced simultaneously. After the end of the initiatorfeed the reaction mixture was held at 140° C. for 2 hours more, thendiluted with 119.6 g of the aromatic solvent described, and subsequentlycooled. The resulting polymer solution had a solids content of 60% byweight (determined in a forced-air oven, 1 h at 130° C.). Themethacrylate copolymer had a hydroxyl number of 156 mg KOH/g, an acidnumber of 10 mg KOH/g, a number-average molecular weight of 1,700, and aglass transition temperature of +65° C.

Preparation Example 2

The Preparation of a Methacrylate Copolymer (B) Containing Hydroxyl andCarbamate Groups

A laboratory reactor having a useful volume of 4 l, equipped with astirrer, two dropping funnels for the monomer mixture and initiatorsolution respectively, a nitrogen inlet pipe, thermometer, and refluxcondenser, was charged with 176.7 g of an aromatic hydrocarbons fractionhaving a boiling range from 158° C. to 172° C., 188.8 g of methylcarbamate and 345.9 g of Cardura® E-10 (glycidyl ester of Versatic®acid, from Shell Chemie) The solvent was heated to 140° C. After 140° C.had been reached, a monomer mixture of 312 g of hydroxyethylmethacrylate, 85.4 g of cyclohexyl methacrylate, 117.41 g of methacrylicacid and 59.6 g of the aromatic solvent described and an initiatorsolution of 73.9 g of azoisovaleronitrile in 36.7 g of xylene weremetered into the reactor at a uniform rate over the course of 1 hour.The reactor was furnished with a distillation bridge. Then a solution of2 g of dibutyltin oxide in 106 g of xylene was added and the mixture washeated to 135° C. It was held at 135° C. and methanol was distilled offcontinuously until a hydroxyl number of 90 mg KOH/g was reached(determined by titrimetry). Thereafter, excess methyl carbamate wasdistilled off under reduced pressure at 14° C. for a period of twohours. The resulting polymer solution was diluted with methoxypropanolto a solids content of 70% by weight (determined in a forced-air oven, 1h at 130° C.). The resin had a carbamate equivalent weight CEW of 440.The equivalents ratio of hydroxyl groups to carbamate groups was 1:1.4.

EXAMPLE

Preparation of a Clearcoat Material and Production of a Clearcoat

175 g of the methacrylate copolymer solution (A) of preparation example1, 352 g of methacrylate copolymer solution (B) from preparation example2, 194 g of a butanol-etherified melamine resin (Cymel® 1158 fromCytec), 12 g of a blocked acid catalyst (Nacure® 2500 from KingIndustries), 10 g each of Tinuvin® 248 and 123 (light stabilizers fromCiba), 2 g of a commercial leveling assistant (silicone oil) and 212 gof xylene were mixed thoroughly. The ratio of hydroxyl groups tocarbamate groups in the clearcoat material was 1:0.8, and 77% by weightof the hydroxyl groups present in the binders (A) and (B) were primaryhydroxyl groups.

The clearcoat material was applied wet-on-wet to test panels which hadbeen coated with black aqueous base coat films. The resultant aqueousbase coat films and clearcoat films were baked at 140° C. for 20 minutesto give test panels bearing multicoat paint systems composed of a blackaqueous base coat and a clearcoat. The multicoat paint systems with ablack aqueous base coat were chosen since they best allowed the changein the appearance caused by mechanical damage to be observed.

The scratch resistance was determined by the Amtec-Kistler test, whichis known in the art, using 1.5 g/l Sikron SH 200 ultrafine quartz powder(cf. T. Klimmasch, T. Engbert, Technology conference, Cologne, DFO,report volume 32, pages 59 to 66, 1997). The gloss to DIN 67530 ismeasured before and after damage (measurement direction perpendicular tothe direction of scratching).

Free films were produced from the clearcoat materials, and these filmswere analyzed by DMTA. As a measure of the crosslinking density/scratchresistance, the storage modulus E′ in the rubber-elastic range wasascertained.

The key to the results indicated is as follows:

-   -   Gloss initial gloss (200) prior to damage    -   dGloss loss of gloss after damage relative to the initial gloss

E′ storage modulus in the rubber-elastic range of the DMA Inventiveclearcoat material Gloss 90.2 dGloss 22.1 E′ 2 × 10⁷

The multicoat systems also exhibited particularly high resistance to FAMstandard test fuel (50% by volume toluene, 30% by volume isooctane, 15%by volume diisobutylene, 5% by volume ethanol, in accordance with VDA[German automakers association] test bulletin 621-412, based on DINstandard 53 168). Their acid resistance, according to the Opel test GME60409, which is common knowledge in the art, was outstanding.

1. A coating material comprising: (A) at least one hydroxyl-containing(meth)acrylate (co)polymer having an OH number of from 100 to 250 mgKOH/g, an acid number of from 0 to 35 mg KOH/g, a number-averagemolecular weight M_(n) of from 1,200 to 20,000 daltons, and a glasstransition temperature of not more than +70° C., (B) at least onecarbamate- and hydroxyl-functional compound having a hydroxyl number offrom 10 to 150 mg KOH/g, a carbamate equivalent weight CEW of from 250to 700 g/equivalent and an equivalents ratio of hydroxyl to carbamategroups of from 1:20 to 1:0.5, and (C) at least one amino resin; where(I) at least 10 equivalent % of the hydroxyl groups present in the(meth)acrylate (co)polymers (A) and/or the compounds (B) are primaryhydroxyl groups and (II) the coating material, after it has been cured,has a storage modulus E′ in the rubber-elastic range of at least 1.5*10⁷Pa, the storage modulus E′ having been measured by dynamic mechanicalthermoanalysis (DMTA) on homogeneous free films with a thickness of40±10 μm.
 2. The coating material as claimed in claim 1, wherein theglass transition temperature of the (meth)acrylate (co)polymers (A) isfrom −40 to +70° C.
 3. The coating material as claimed in claim 1,wherein the (meth)acrylate (co)polymers (A) have a hydroxyl number from160 to 220 mg KOH/g and/or a number-average molecular weight M_(n) offrom 1,500 to 15,000 daltons.
 4. The coating material as claimed inclaim 1, wherein the methacrylate copolymers (A) are prepared bycopolymerizing (a1) from 10 to 51% by weight of a compound selected fromthe group consisting of 4-hydroxy-n-butyl acrylate and 4-hydroxy-n-butylmethacrylate and mixtures thereof. (b1) from 0 to 36% by weight of acompound selected from the group consisting of a hydroxyl-containingester of acrylic acid and a hydroxyl-containing ester of methacrylicacid, and mixtures thereof, where each is other than (a1), (c1) from 28to 58% by weight of a compound selected from the group consisting of analiphatic ester of (meth)acrylic acid having at least 4 carbon atoms inthe alchohol and a cycloaliphatic ester of (meth)acrylic acid having atleast 4 carbon atoms in the alcohol residue, and mixtures thereof, whereeach is other than (a1) and (b1), (d1) from 0 to 3% by weight of acompound selected from the group consisting of ethylenically unsaturatedcarboxylic acids and mixtures thereof, and (e1) from 0 to 40% by weightof compounds selected from the group consisting of a vinylaromaticmonomer and an ethylenically unsaturated monomer and mixtures thereof,where the monomer is other than (a1), (b1), (c1), and (d1), the sum ofthe weight fractions of components (a1), (b1), (c1), (d1) and (e1)always being 100% by weight.
 5. The coating material as claimed in claim1, wherein the methacrylate copolymers (A2) prepared by copolymerizing(a2) from 10 to 51% by weight of a hydroxyl-containing methacrylate(s),selected from the group consisting of hydroxypropyl methacrylatehydroxyethyl methacrylate, and mixtures thereof, (b2) from 0 to 36% byweight of a hydroxyl-containing ester(s) selected from the groupconsisting of a hydroxyl-containing ester of acrylic acid and ahydroxyl-containing ester of methacrylic acid, and mixtures thereof,where the esters is/are other than (a2), (c2) from 28 to 58% by weightof an ester selected from the group consisting of aliphatic esters andcycloaliphatic esters of (meth)acrylic acid having at least 4 carbonatoms in the alcohol residue, other than (a2) and (b2), a and mixturesthereof, (d2) from 0 to 3% by weight of compounds selected from thegroup consisting of ethylenically unsaturated carboxylic acids andmixtures thereof, and (e2) from 0 to 40% by weight of monomers selectedfrom the group consisting of vinylaromatics monomers and ethylenicallyunsaturated monomers where said monomers are other than (a2), (b2),(c2), and (d2), and mixtures thereof, the sum of the weight fractions ofcomponents (a2), (b2), (c2), (d2) and (e2) always being. 100% by weight.6. The coating material as claimed in claim 1, wherein the compound (B)is a (meth)acrylate (co)polymer containing hydroxyl groups and carbamategroups.
 7. The coating material as claimed in claim 1, wherein thecompound (B) has a hydroxyl number of from 15 to 120 mg KOH/g.
 8. Thecoating material as claimed in claim 1, wherein the compound (B) has acarbamate equivalent weight (CEW) of from 300 to 600 g/equivalent. 9.The coating material as claimed in claim 1, wherein the ratio ofhydroxyl groups to carbamate groups of the compound (B) is from 1:15 to1:0.8.
 10. The coating material as claimed in claims 1, wherein theratio of the hydroxyl groups of the constituents (A) and (B) to thecarbamate groups of the compound (B) is from 0:10 to 1:0.5.
 11. Thecoating material as claimed in claim 1, wherein at least 15 equivalent %of the hydroxyl groups present in the (meth)acrylate (co)polymers (A)and/or the compounds (B) are primary hydroxyl groups.
 12. The coatingmaterial as claimed in claim 1, wherein the crosslinking agent (C) is amelamine resin or an amino resin mixture having a melamine resin contentof at least 60% by weight, based on the amino resin mixture.
 13. Thecoating material as claimed in claim 1 comprising at least one furthercrosslinking agent (D) which is different than (C) and is selected fromthe group consisting of components which crosslink with the hydroxylgroups of (A) and/or (B) to form ethers and/or esters, and/or of blockedand/or nonblocked polyisocyanates.
 14. The coating material as claimedin claim 1 comprising at least one of an additive (E) a pigment (F). 15.The coating material as claimed in claim 1 which after it has cured hasa storage modulus E′ of at least 5*10⁷ Pa.
 16. A process for preparing acoating material as claimed in claims 1, in which (A) at least onehydroxyl-containing (meth)acrylate (co)polymer, (B) at least onecompound containing carbamate groups and hydroxyl groups and (C) atleast one amino resin, are mixed with one another and the resultingmixture is homogenized, wherein the constituents of the coatingmaterials are selected such that (I) at least 10 equivalent % of thehydroxyl groups present in at least one of the (meth)acrylate(co)polymers (A) and the compounds (B) are primary hydroxyl groups and(II) the coating material, after it has been cured, has a storagemodulus E′ in the rubber-elastic range of at least 1.5*10⁷ Pa, thestorage modulus E′ having been measured by dynamic mechanicalthermoanalysis on homogeneous free films with a thickness of 40±10 μm.17. Compounds selected from the group consisting of coatings, adhesivefilms, seals, moldings and self-supporting films comprising coatingmaterial as claimed in claim
 1. 18. The coating as claimed in claim 17,comprising a coating selected from the group consisting of clearcoatsand pigmented coatings.
 19. A coating as claimed in claim 18, whereinthe coatings is a multicoat paint systems.
 20. A coating as claimed inclaim 19, wherein the coatings is a clearcoats of a multicoat paintsystems.
 21. The coating as claimed in claim 17, wherein the coatingsexhibits a gloss difference in the AMTEC test of less than 35 units.